AudioNervosa
Systemic Development => Speakers => Topic started by: richidoo on October 17, 2007, 05:47:35 PM
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Frugal-horn.com shows a DIY design "Big Vent Reflex" pseudo horn speaker cabinet. The designer, Scottmoose on diyaudio.com, modified (http://www.diyaudio.com/forums/showthread.php?postid=1318611#post1318611) his Suzy Chang BVR design specifically for the new Feastrex driver's performance specifications, using Martin King speaker design software. I built a pair out of pine to retain full "mother-of-tonism" and finished them up today. I installed Feastrex D5nf drivers, and connected to Altmann Attraction DAC and BYOB amp with home depot wires. Wow. Spider web - good luck getting away from this... It is intensely emotional, microscope detail, with rich, realistic harmonics. Dynamics, frequency range, musicality are amazing. A lot of this is the Altmann stuff, but the speaker is doing it's part, no doubt.
(http://parkwestlake.com/nopw/rich/moose.jpg)
I wanted to name it "MooseFeast 5" but that didn't take.
It needs some tweeking, the cabinet is resonant and the image is low (these boxes are small) but the sound is amazing. It is definitely full range, with no apologies. I can feel tight clean bass physically. It goes low enough to play symphonies with authority and funky Boney James dance music with full mojo, although not the kick in the stomach feeling of the Legacys. Mids are clear and clean, highs are very extended, no tweeter is necessary. No highs are missed. My beloved bells and chimes sound sweet and rich. When I switched back to the main system, I missed the Feastrex right away, but the Legacys are clearer, more hifi (lower distortion maybe?) greater extension yada-yada...
I am very excited about this system. Lots of tweaking to come. I will post FR as soon as I can do it. Anyone is welcome to come over to hear it anytime. I will try to pull together a G2G soon now that RMAF is over.
Rich
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Sounds like the perfect speaker for a slightly smaller room... with the Altmann system attached... hmmm... Just a thought.
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Good idea! It might live upstairs in a smaller room, or come apart for an OB project next... :) It needs 200 hours breakin, amp needs 50, so I will let it cook before any major changes. I look at it as something to tweak and play with, make changes and learn. I like the purist audio aspect of it, soothes my nervosa in a big way by eliminating major areas of anxiety - crossovers, multiple drivers, AC power supplies, cables, etc. I'm relieved it doesn't totally suck. I can actually sit in front of it and enjoy for extended period. Amazing for a first time DIY speaker -hehe I was expecting much worse.
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Richadoo,
Looking good man. Keep us posted.
rollo
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Those look beautiful, Rich. What a motivated learner you are! What you have going there is diametrically opposed to your other setup but you're openminded enough to dive into the deep (other) end. Kudos, man.
When I decided to try the single driver thing out I bought a cheap pair of Fostexes and built a pair of bass reflex boxes out of MDF. They sent me off on a crazy tangent from which I haven't recovered but they're trolls compared to your catwalk hotties. I'd sure like to hear 'em.
Wanna feel good about your work?
http://www.audiocircle.com/gallery/thumbnails.php?album=687 (http://www.audiocircle.com/gallery/thumbnails.php?album=687)
What's the sensitivity of those buggers? I'm upgrading my Def. Pros to 2s and I have to sell the Yamamoto A-08s to fund it :duh but I'd sure like to get that amp in a room with those speakers. I didn't know you were getting the Altmann amp with the DAC but I bet they're a match made in single driver heaven. Still, SET tubes . . .
I recently got a pair of first generation Omega hemptone 8"ers to swap in for the Fostexes. I like them better but now the bass ports are funky, as in I have to replace them. I think the tuning is too high and it's muddying things considerably. I have them sitting in my car-vacant garage, neatly spaced for "soundstaging". It's quite a vision actually, those ugly buggers sitting in a cluttered garage with wooden, folding chairs for "listening seats". I'm running it all off a discman and gainclone amp and y'know, close your eyes and it ain't half bad.
Anyway, thanks for sharing Rich. I really look forward to hearing your accounts.
Mike
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Richadoo,
Can Altman make the Amp mono? One in each enclousure,maybe? Some cross bracing of cabinet, Black hole pad, spikes and,and. Sorry Nervosa setting in. Oh my!
rollo
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Mike, thanks for the encouragement. I really appreciate it. I dug your pics, especially the subtitles hahaha Those look great. I haven't done much with SET yet on the power amp end, but I loved the Art Audio 845 amps in the Daedelus room. That was pure sex, as were the huge 200w radio transmitter tube SETs. If you don't need to be in that same room with Yammys and Feastrex, send em on! hahaha I guess I could send my speakers over too, and with less risk...
So much hype about this alternative hifi stuff, I just had to bite to see if any of it is true. It is true, but is still very different than our American muscle and refinement through technology approach which of course is superior in everyway except transmitting the glory of God, which is why I listen to music anyway. That's what makes the japs go nuts over this wacky DHT amp and paper driver shit. It is pretty cool, but it exacts its cost in several ways, in money and in departure from perfect distortion specs which American model is based on. I say American as opposed to European which also follows the distortion spec model only because Americans are less willing to sacrifice the lowest octave which requires 4x power and 4x bigger speakers to maintain same low distortion as upper octaves.
BTW, the Zu Defs were used as reinforcement for singer at the show. They sounded really great. Much better than the demo room they were in last year with local dealer.
The Altmann amp is pretty cool. Mine is used and the seller voided warrantee by removing from the wood board (actually cut in half trying to put inside a box :roll: ) But the discount was worth it and now I am free to have a close look at what's going on. The amp's PCB is not setup for running as monoblock, but maybe L/R input signals could be rigged for mono input yielding a monoblock, or at least a biamper. I would have to really think about it and get some help to try that. Expensive if I screw up. Power is an issue for me using it with the Legacys. The amp sounded incredible on first day, so I think it is worthy, then developed a distortion while playing some brass quartet stuff which is demanding on current - long mid and low freq sinewaves at medium volume, but the Focus is 2ohms at 75Hz, right in Tuba land. Heatsinking was not good as received. It looked like stock, but I think that maybe the seller did not reassemble the heatsink correctly, which allowed overheating. I improved the heatsinking, but not sure if the chip is already damaged. It is supposed to have a lot of protection modes for heat and shorting. But I can hear a little bit of ick in there after it warms up, even with the 16 ohm Feastrexes which offer tiny load, they are 97dB@16ohms. I will ask Charles what's up, maybe he can solder on a new chip and check it over. But yeah, the sound is really something very special. I would love to have 4 of the them running as monoblocks hanging like ornaments off the high and low speaker posts behind my speakers, with a battery on each side. Add it to the list of to-do's haha. It would cost $4000 list to buy them new. But actually it would probably be worth it compared to similar performance from AC powered 4k retail amps. To get this kind of bass you would need 200w+ ss per side. Unbelievable bass. Once I make sure it is healthy I will send it on a tour.
Snappers sound great on the new speakers too. Lots of power reserve, and ease playing big music.
Rollo, you are absolutely right about the tweaks, and they are coming, even the black hole, bracing, and another trick used in Feastrex' own speaker boxes, mounting the driver from behind on a crossbrace in side the cabinet and isolating driver from front baffle altogether. Still raw wood too, might put a coat of something natural on there which will tone down the mid hype I think. Altmann suggests homemade turp and resin, but that will stink for a long time.
Rich
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Rich,
For the finish, consider antique oil or an oil rub... Linseed or something like that... It's natural, penetrates, leaves a nice luster, and is easy to maintain... It dries fast, doesn't smell, etc. I've refinished pine with it before with excellent results.
-C
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Richadoo,
What about simple Varnish as a finish? So whats a little smell. It goes away.
rollo
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Thanks for the finishing advice. When I'm not audio-insane I use General Finishes (http://www.generalfinishes.com/finishes/oil-base-finishes/oilbase.htm) products which are awesome. But they have poly in them, and musical instruments should have a natural resin based finish. Altmann and his "mother of tone" stuff suggests dissolving colophony (tree resin) in terpentine. This has reputation of drying VERY slowly if at all. Actually I am thinking now that it is a little over the top anyway, so I may just stop worrying about it. haha The smell of terp doesn't bother me, but mineral spirits does, especially if it dries slowly and lasts for months. I'll have to experiment a little.
I wrote to Altmann about the distortion, he replied quickly with advice I should have thought of. Charge the battery dummy... (my words, not his...) I was using a new battery, and knowing it was pre-charged I didn't bother to get a charger yet. But without load the battery is at 12.5V. With a 5A load, voltage will drop farther and make the chips distortion go way up. At 9volts it is a total wimp. Chip can source 9A and I bet the Legacys are drawing that on peaks. So now it's on charge, and I'm looking forward to that great sound coming back. Sorry for the false alarm, I overreact when I think things are prematurely broken.
The drivers are loosening up a lot, sounding better. My wife and oldest son think they sound the same as the big speakers. For once I thought that was positive news. :) Wife heard the Altmann's clarity immediately on first night, when battery was still charged.
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Rich,
Sounds very, very cool! Just don't overdamp or overbrace the cabinet, and you might find that some cotton or wool felt padding may work better (and cost a lot less than BH5.) And when you're ready to try another type of cabinet, the Mileva monolith-type (sideways turned QW pipe) should be able to be tweaked to work with the D5. It's the smaller brother of the "Demetri" that I heard in Michael Mardis' room. It is also designed for the driver to be in contact with one of the braces.
Keep us posted -- this sounds really fun and interesting.
-- Jim
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Thanks Jim, that sounds interesting. Another cabinet design created especially for the driver came across my email yesterday. It is a small box and has a simple TL inside the box. I thought TLs had to have an exhaust vent to ambient pressure, but this one seems to be a sealed speaker with dead end TL. Picture here. (http://www.audionervosa.com/index.php?action=gallery;sa=view;id=114) Is that possible? It is a quicky napkin sketch with no details, so maybe it is just understood that it should be vented, but not understood by me! It is supposed to make the driver sound like OB, using Martin King TL parameters. Actually after looking up your Mileva design, Jim, I see a bunch of dead end TLs called ML-Voigt. What does ML mean? The Mileva design looks cool. I wonder how to modify it for a different driver. I need to buy and learn to use Martin King's spreadsheets.
After more listening yesterday, I am starting to hear the wood's resonant contribution, and the slight shoutiness of the horn mouth. So some damping is required. I intend to rear mount the driver on a beam across the inside of cabinet which will stop some of the box ringing, then tape some newspaper balls into the corners, etc. At least for a start. Maybe some towel layers for reflection damping. There is a sealed empty volume under the slanted board that makes the horn. I am thinking of filling that up with spray foam urethane which expands and should lock the walls tight. Any opinions on that method, besides don't use too much? I know it can rip the box apart as it expands. I also thought of filling it with concrete, but I like the portability of these speakers, something I don't have with the 185 pound Legacys.
Thanks
Rich
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Rich,
ML = Mass Loaded.
As for dead-end pipes, haven't a clue -- never heard of it, but that doesn't mean much.
One thing I used to do in the speakers I built back in the 80s was to use a piece of cotton rope -- maybe 3/4" - 1" glued along the seams. The same kind of stuff you might find used as mainsheets on a sailboat (wonder where I got the idea :-) ). As for lightweight filler,, again, I have no particular recommendation as I've never used anything like that, but my guess is that the various things like sand, shot, BBs, etc. while filling the empty space and stiffening up the surfaces it is in contact with, also help to add solidity to the speaker as a unit, and damp the box movement, and anchor it to the floor better. Still lots of experimenting to do here, but I feel pretty hampered without access to drawings, etc.
Another finishing option that I have used and love, and which as been around forever are the poly/oil finishes from General Finishes -- a small company somewhere in Minnesota. They are wipe-on, come in a few finish textures from satin to high gloss, and also include a pre-sealer that really brings out the grain in the wood. I used to use a single coat (no more) of their Seal-A-Cell, followed by as many coats as you wish of the Arm-R-Coat. People have reported these finishes to look as good at 40 years as the day they put them on. It is also a really great finish to use for the bases and wood panels on tube amps because it is very heat resistant.
Between your experiments, what I saw at RMAF, and the ideas I've been kicking around for a while now, I've finally reached the point where I just need to grab the bull by the horns and figure this thing out -- how I can read drawings, graphs, etc. I have a high-resolution tactile graphics printer (4x the resolution of standard braille), and software that in theory will let me print this kind of stuff, that I've been playing a role in the development of for the past 10 years, and now it is time to see if it can do more than simple charts, etc. If I can get this working reasonably well for PDFs of drawings, FR plots, and schematics, then I'll be a happy camper. I've got room cleared on my desk now, so today is the big day to try a few test prints and see what happens. Keep your fingers crossed.
-- Jim
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That would be awesome Jim, good luck. I'll help however I can.
Bryan Pape sells cotton insulation which is great for acoustic absorbtion. Mashed into interior corners I think it would along same line as rope, but maybe a little more porous. Great idea.
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Good luck with that, Jim. You are a resourceful dude.
In my BR boxes, I used thin carpet underneath and pillow batting on top to line the driver chamber. It has sensible visual effect but I have no clue what the acoustic benefits are. It WAS cheap.
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Rich,
Any updates?
Looks like I've settled on another Scottmmoose BVR enclosure -- Harvey -- for my F120As I also managed to get one of my cabinetmaker/audiophile buddies interested in wanting to build these with me. Probably going to do at least the main parts of the box with 3/4" Apple plywood, which I also just found out I can get at a local hardwood place.
-- Jim
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Your project sounds like a lot of fun. That apple ply sounds gorgeous, can't wait to see it. I was surprised at the bass response of mine in the BVR cabinet. He is a talented designer. The inside plumbing is wild on some of his stuff, but the outside looks pretty cool. Here is a picture of Harvey:
(http://homepage.mac.com/tlinespeakers/FH/images/spawn-masked-mtn.jpg)
Info (http://frugal-horn.com/spawn.html)
I listened a lot to mine when they were first finished. Then I switched back to Legacys, enjoying the Altmann amp on them. Then a couple days ago I switched back to the BVRs and fell in love. I don't know if something changed, or my mind was ready for it, but somehow it just hit me. Listening to this record (http://www.arkivmusic.com/classical/album.jsp;jsessionid=013CEA39C363A4DDD008C8819A468D74?album_id=176798) on the radio was a hifi peak experience. If you ever thought you liked violin, this might be the best technical recording I have ever heard of violin. I got the CD on the way to hear it with no compression. Anyway, I think the drivers are really breaking in well now, and the music is really coming alive. The Altmann is broken in now too, maybe the combination of new stiff parts was offputting, despite the fun detail (Miklorsmith you listening? - haha). It is spine chilling now, hard to walk away. I would like to tame the wood box resonance, and a ton of bpape's cotton insulation arrived today, so I will try some 1" thick cotton in there, plus some cross dowels to brace the sides. I am still using cheap speaker wire, so that's another tweek waiting. But I love them. Lotsa fun.
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Yup, just put a hold on the last two pieces of 3/4" apple ply, and hope to pick it up sometime this week. I'll probably use a wedged dowel crossbrace too, and a brace against the magnet structure that can have it's pressure against the driver adjusted from the back with a socket head bolt.
So, you know that amplifier that there was only one of left? You have to know I bought it, right? :D
I think the combination of these cabinets and the drivers are going to make for some great listening in my office, especially when Ms. Carina arrives.
I'm supposed to be getting some nice wire to make small gauge speaker wires with, so if and when that happens, and the results are good, I'll be happy to make you a pair.
-- Jim
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Speaker wires! Now you're talkin! Thanks I wish my JPS could fit up through the vent to reach the drivers, but I don't want to bend them all to hell, so Home depot wire is working fine.
Theres a Feastrex owner in Boulder (?). He is contemplating building the same cabinet that I did, at least until he can build an OB for them. Let me know if you wanna get in touch. He's an angel like you.
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Richadoo,
Great CD. Sarah Chang takes me away. Must sound wonderfull through that single driver. Looking good man. For me the only single driver speaker Iv'e heard that did not beam at me was the Cain &Cain Wall of Sound. Love to hear the MooseStyle some day.
rollo
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Cool stuff guys, what neat projects. I REALLY need to finalize my teleporter design. :D
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Thanks for the support guys. I forgot to mention that I did a half ass mesaurement of the bass response last week. At 90dB Pink noise, it rolls down -6dB at 70Hz, and -15dB at 60Hz. Not too bad, bass is enough to support mids and sound full and musical most of the time. Sometimes I switch to Legacys for full satisfaction, but I always come back, it is addictive.
Yeah, Mike I hope you have your teleporter done before I pop in on you next summer. You have too much great stuff going on for me to not come listen sometime. Don't worry I'll leave the kids at the hotel. hehe
rollo, I have not heard a lot of Chang yet, but you know I recently turned into a violin nut. Started with Julia Fischer, the German dictator of technique and power, probably the greatest that ever lived, but will not warm your heart except by nuclear explosion. I like Rachel Barton, American smoothie, and of course Hillary Hahn but neither really light my fire, standard issue great violinists (what a world of abundance!) Then I heard Kyoka Takezawa (http://www.audionervosa.com/index.php?topic=230.0) live last year, wow. That forced me to crack open my mind to seek out more than Fischer. Chang is right up there for her incredible sensitivity while avoiding fake classical mellodrama that I am strongly allergic to. Anyway I hope to get some more of her stuff, and I hope it is all recorded as well. EMI classics is the label.
My 7yo son took home a 1/2 sized violin last Saturday, will start lessons after Christmas. He is excited to learn it and picked it on his own, but I hope he is not doing it to please Daddy, what a tough instrument. People that can play it like these ladies really have my respect.
Rich
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I have warm smiles and cold beer for any crazies that wander my way.
Seattle's a gas in the summer too.
I put that Chang on my buy list, I'm no violin nut but I can learn.
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Wow, nice wood work! I wish I didn't suck at it but I usually end up with crooked pieces, misalignment as well as blood all over the wood which, by the way, is actually a pretty cool looking "stain"!:duh
John
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Wow, nice wood work! I wish I didn't suck at it but I usually end up with crooked pieces, misalignment as well as blood all over the wood which, by the way, is actually a pretty cool looking "stain"!:duh
John
Its called Passion Red. He He he.
rollo
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Had a fun nite of listening to the Feastrex "Beavers" last night. Since last G2G I have removed ALL of the bracing and internal absorption which made it sound like crap. Even my wife said it shrieked. I didn't listen to it for a few weeks. Without that stuff in there they sound much better again. I took them apart again this weekend to test the drivers using Woofer Tester 2. It is a little annoying like all small company software, but it gets the job done with a little persuasion. Anyway, when I put them back together again, I was able to make some adjustments. I moved the rubber gasket in a little to a smaller radius which covered up the screw holes I originally used for driver mounting to the baffle. I rear mounted the driver but the baffle mount screw holes were still there, leaking air. I like to imagine that gained me another 10dB at 50Hz... haha I wish! Then I replaced a shortish speaker wire with a long one, allowing me to place the speakers out 10+ feet from the front wall where the amps are. Magically, all my room acoustic problems vanished! (Atleast what I could notice in one days' listening - it is much improved with reflections now being 3-4x longer distance than the direct distance of only 6 feet) With single drivers you can sit very close and it stays perfect.
I was once again overwhelmed by the beautiful tone, lightning fast detail and pure crossover less smoothness and openness. I can hear more than ever now all the colorations comeing from the box itself. While my wife sat in the sweety spot (renamed in her honor) I moved to behind and off to the side. I could still hear plenty of treble detail and the magic of the music, but I could also hear all that bass leaking out of the loosy goose cabinets made of un-braced solid pine board. I am giving the cabinets to a friend in CO and might rebuild them again in birch ply which should cut the resonance down a lot.
There is also another Big Vent Reflex (Beaver) design, by same designers Scott and Dave over at Planet 10, called Maiko - similar to their popular Harvey design. It will be two horns top&bottom instead of instead of just one on the bottom like mine. The driver height will be higher and bass should be faster and lower. I am hoping for the best with it. I will build that one before I build another of these shorty versions.
I have guests coming over tonight so I won't be able to listen until they leave at 9. Can't wait!! haha It is fun to switch back and forth between a straight laced hifi, full range design like 5 way Legacy Focus and the single driver horn Feastrex. They are both great in their own way, but each has special magic of its own. My goal is to get the Feastrex to carry as much water as the Legacys which will require bolting on some serious air pumps on the bottom, and tweaking out a little of the midrange "personality" that is inevitable with a 4" paper driver. Not sure it can be done, but I think it is worth a little effort to try. I'm sticking them into an open baffle this week, just by themselves to see how much that box is really coloring, see how pure the drivers sound with no excuses before I start buying love presents for them like woofers and amps for the lows.
Thanks
Rich
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I have been asked by a fellow ANer to post the latest news from the Feastrex NC research lab.
I have been digging them, of course. They have mellowed out and are very exciting and musical to listen to. A few more people around the world have bought the drivers and built this same cabinet per plans that I posted on diyaudio, designed by scottmoose and Martin King. It allows the speaker to speak clearly while giving a decent bass extension, considering it is a 4" driver.
I built mine in solid pine, which turned out to be very lovely sounding when it wasn't resonating with the music. But when it did resonate (most of the time), the coloration was severe. Still listenable because it is pine wood box and paper cone with all tubes, so what's not to like... But to a perfectionist like me, eventually it started to get on my nerves everytime the cellist played my jaw would rattle. So I gave away those boxes to a friend in CO, Mike who worked the Feastrex room as translator for Mr Teramoto when he visited for the RMAF show.
I'm waiting for a new design to emerge from planet-10 audio, designed by scottmoose and Dave Dlugos, which will be more highly optimized for the driver than the original "Freddie Chang" that I built. It is larger coupling chamber, and two horns instead of one, looks like the Harvey pictured above. But until that is born, I am gonna rebuld the smaller Freddie cabinets again, this time using a different approach, and hopefully kill off most of the cabinet resonance. Read TAS interview with Magico's Alon Wolf this issue to get an idea what I'm thinking about.
I have also used Martin King's mathCAD sheet to design an open baffle for these drivers. I have them playing now, and they sound incredible. All crap from the box is gone. But alas, no bass. But there is a lot of that box sound that I like, and miss, or at least for the first 10 minutes. OB is very natural and uncolored, but we like our distortions and get very used to them. Strip it all off and it seems less exciting, more plain. But the ease of listening is so much better. It just wafts through you with no pressure at all. The simulator says it rolls off about 12-18dB starting at 200Hz, but dead flat above that. I bought a pair of Peerless XXLS 12" drivers to mount in the baffles and hope to do that this week. They are ultra low distortion bass drivers with gigantic excursion. I think they will be fast enough to keep up with the 2g moving mass of the Feastrex, I hope so. Modelled in mathCAD with the woofers and no boost, the OB speakers are flat down to 100Hz with no woofer frame and no boost, woofer only moving 3mm out of its possible 13! and rolling gently down to -12dB at 30Hz.The Peerless will need a lot of power, but I can crank in some boost to flatten them out as necessary using...
I also got a Behringer DCX2496 xover. I ordered the upgrade kit from Pilgham Audio. It will be a while before that is running, but mgalusha says it is a great mod. They are bringing out more kits for DCX coming soon.
So far I can only say about the Feastrex drivers that they sound effortless, smooth, rich, ultra detailed without any edge or annoying factor. The bad thing is that I can hear everything that is wrong with my electronics. Hum, tube tinks, hiss, whatever, it is an electron microscope. It is hauntingly real with music that compliments its one limitation of little bass. In the BVR cabinet, bass is flat down to 70Hz, so you can easily enjoy any music, and even feel it in the chest now and then. The treble response is just like a separate tweeter, but richer, more natural, cymbals sound real, instead of metallic. Extension on things like chimes, bells, tinkly things is much stronger sensatioin than my ribbons on my Legacys, which I recently learned are just cheap $20 planars, well implemented... Voices like Alison Kraus or Tallis Scholars just melt me. String quartets are awesome. Symphony is also good, and plenty enjoyable, but I miss the vibration of low notes on bass violins. My wife's Chris Daughtry is not as exciting as on the big speakers - duh. So I keep experimenting. I'm hoping the new design from planet 10, to be called Maiko, will give the extra bit of bass that is needed to make a truly high end speaker. If not, the 2 way OB will work good.
The drivers have a lot of inner detail especially in the midrange. This makes them very magical, and special sounding from the very first note. It is a funny tradition starting now to to observe people the first time they are deflowered hearing Feastrex for the first time. Audible moans and groans, explitives of disbelief, wanting to talk about it and listen at the same time, and excitement, like a crack head wanting to score a fix. haha It is an easy sell, except for the price. But compared to many $4000 speakers (like mine) this kicks ass for pure enjoyment. You also have to factor in improving the electronics. No point in having all that resolution with a suitable signal to play, or too noisy.
I also plan to do another anechoic experiment with them, which is the reason I bought them actually. That is starting to come together now. Shitty weather slows down wood cutting.
As for where to get them, Joe Cohen of Lotus Group is the importer. They list for $4000 pair for D5nf the drivers only. Other models available, but these are the cheapest - oops, sorry Bill, I mean least expensive... ;) Delivery is about a month, fresh from Japan. Contact Joe by email on his website, or call him. Any Lotus Group dealer should also be able to order them for you. I got mine from Dennis Jeffers in Charlotte, NC, helluva nice guy.
There are a lot of posts about the drivers and these cabinets on the web now. Google will get you there, or check out diyaudio, asylum (search chris witmer, or just feastrex), and now some action on AC with floobydust just finishing his pair, and loving it. puremusicgroup.com has forum with Feastrex section.
I think the excitement abot them is building up steadily. They just had a good show at CES, with mention on stereophile blog and 6 moons but there is a long way to go yet.
I will play mine again at the next meet we have here in NC, hopefully they will sound a lot better than last time when I screwed them up badly with incorrect bracing and absorbtion inside. Live and learn. I will never forget the look on Shane's face like he fell on an icepick. :rofl: These NC audiophiles are tough please.
It is expensive, but on first listen, you will understand why. Hopefully by next year's trade shows, the cabinets will be sorted out to allow their incredible sound to be obvious to more show goers. Feastrex's own bass reflex and passive radiator deisgns were not optimized at RMAF, so the $50 diy Freddie sounds much better IMO, maybe a little less bss, but much more a whole cloth.
Sorry if I repeated myself or rambled. Hard to avoid with me..
Rich
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WOW, great w/u! Stupid nonworking teleporter. . .
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I built a new cabinet for the Feastrex drivers. Finished them yesterday. It is a prototype design by planet10.com called Maiko. The final version will look fancier. This is rough and tumble to work out the tweaks.
It plays very big, and has great frequency response. The baltic birch has a "unique" sonic signature that I am trying to reign in with bracing. Pine is much more pleasant sounding, but it can be too warm in large unsupported areas. The smaller speaker I built last time was ruined by adding bracing, so the concept of bracing is still a black art to me. It seems to make the resonance worse by raising the frequency, until it gets so high that it becomes inaudible. That's the theory anyway. I am prepared to laminate on some pressure treated 2x12s if the tensioning rods and bracing don't cut it. :twisted:
I will be playing them at the G2G this weekend. Hopefully earmuffs will not be required this time. Last time we played the drivers with the Cary integrated which is a little fussy about the load impedance. The drivers are 14.5 ohms connected to Cary's 8ohm tap making upper mids stand out so much that people went running away covering their ears! It was the perfect storm of too much dowel bracing, combined with the wrong amp that I had never tried before. Pulling out all the treatments and using the SNappers on that small cabinet was very impressive, but lite in the bass.
These bigger ones have great bass. What does great bass mean in single driver parlance? Designed to be flat to 50Hz, I can feel satisfaction listening to low piano notes down to 36Hz. Playing Bob Marley overblown electric bass guitar I can hear all the notes, but only above 50Hz reflex knee do they really boom as intended. Below that they are just notes. Music is entirely digestible. No feeling of missing anything, unless you are golden ear audiophile snob. :^o
Treble is always awesome with feastrex. 4" driver beams highs, so if you sit on the beam your brain will fry. A little toe out is just right. So single driver, <50Hz - >15kHz with no crossover, paper driver, 95dB efficient, 5mm excursion. Dyn-o-mite!!
(http://www.audionervosa.com/gallery/128_25_03_08_12_26_47_0.JPG)
(http://www.audionervosa.com/gallery/128_25_03_08_12_26_47_1.JPG)
(http://www.audionervosa.com/gallery/128_25_03_08_12_26_47_2.JPG)
(http://www.audionervosa.com/gallery/128_25_03_08_12_26_48_3.JPG)
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I wonder how those would sound in your upstairs room?
Nice construction... I wish I had half the woodworking skills you do.
Looking forward to hearing these!
-C
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Congrats, Rich!
How thick is your BB? What are the overall dimensions of the speaker, and what kind of finish do you have on the speaker? Unfinished BB that's too thin for large unsupported areas can sound a bit weird.
And really, a 5 incher that's beaming? Something doesn't sound quite right there -- is there a phase plug?
-- Jim
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Thanks guys. Carl, my tools are your tools. Just sign this liability release form....
Jim, howdy partner! BB is 18mm, aka .69". Speaker is 58" tall, 10" wide, about 14" deep? Going from memory. I don;t have any finish on there yet, which I am starting to gather is not good. Dave recommends a couple coats of varnish or something to cover it up. I love the look of raw wood, but I think that won't fly this time. I was thinking about painting it with latex paint. That will damp even better than varnish, but it is vinyl though. Does that piss off the Audio Goddess of Purity? I was thinking of painting same color as my fireplace - dark green.. Ahhhhh.... that's niiiice..... 8)
I did put some extension clamps across the horn mouths, that helped.
It is a 4" driver, with large wizzer and wooden phase plug. This speaker goes right up to 20k, so it should beam that high at 4" wide. The beam is very high freq. Ducking out of the way is more pleasant for me, leaving the 12-15k stuff where the music is.
So paint it, huh? cool.
Thanks
Rich
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I was thinking more along the lines of a water based lacquer -- or nitrocellulose lacquer (as in musical instrument finish.)
Very time consuming to do right, and the water base is far easier and safer to work with and cleamn up, ammnd either will look beautiful.
If you really like the end result of the cabinet and want to really go crazy, you could build the sides out of glued-up edge grain BB -- the laminations of the ply run perpendicular to the flat surface, instead of parallel to it. Truly masochistic, bbut ultra rigid.
I'm going to try this on a simple BR box for my F120As this summer -- time permitting.
P.S. -- I sent my EnABLed F120As to Planet 10 so they could design an optimized fonken cabinet for them. Like the Maiko, there are a few people who may want to build these, so I volumnteered my drivers to help the effort a bit.
Well, maybe Mike will get his Maiko started fairly soon, then I'll get to hear them. I might suggest two layers of 9 mm BB with a constrained layer of green glue between them for the main pieces -- sides, back, etc.
Wish I could come to the G2G, but foot surgery is going to be happening soon.
-- Jim
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That sounds pretty cool Jim. I never tried water based dope, but sounds interesting. Like you said, it will require many coats to build up any mass, as dope is originally intended to be very lightweight for airplane skin. It dries glossy and has a musical sound because it is actually dissolved wood.
I am getting the impression from various damping experiments that I am doing on the birch cabinets that the BB sound is rather stubborn to dilute. So I'm not sure low mass dope will have much influence, but I never know till I try it. :D I think 4 coats of duct mastic might be more like it to eliminate the birch sound. Yesterday I tried this, (http://parkwestlake.com/nopw/rich/maiko/slab/) it helped a lot but still sounds like birch and is too heavy. It is slabs of treated 2x lumber screwed to the speaker sides with 100 screws per speaker, ever 4-6 inches. The speaker is less confused sounding and images 100% better, but is now way too dark. And still sounds like birch.
There was a cool interview with Magico designer in TAS magazine a couple months ago about wood resonance in speaker cabs. He uses 1" BB on edge like you describe in the Magico Mini and the new V3. I like that idea, but you're right it is tedious, and maybe partly why they cost 30 big ones.
I have some more bracing, tensioning and stuffing to do before I pretend to know the final sound. But I will put wood finishing on the list too. I like the sound of raw spruce, but not BB.
Thanks
Rich
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Man, those are cool Rich. They're bigger than my Defs with six 10"ers each! :D
That kind of woodworking is very impressive to me. When I built my TNT boxes, aside from the sloped front baffle, it was about as simple as it gets. Still, it was a major effort and came out looking like crap. Kudos.
I bet those sing beautifully. I look forward to reading about the impressions when you have your G2G.
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Thanks Mike. It took a little while to build them. Here (http://parkwestlake.com/nopw/rich/maiko/rich/) are some shots of the interior plumbing, it is rather ornate, designed to minimize resonance in the middle box so it won't get amplified in the horns. Notice the driver mounting, it is held in place with a thread rod coming in from the rear. This locks the rear of the driver motor hard against the internal bracing and lets the driver bezel float free of the front baffle, except for a soft rubber or cork gasket. But it all has to be fit and tweaked. It is like a 911 GT2 race car, it rolls out of Porsche factory finished, but not even close to ready to race yet.
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More to report...
The designer Dave Dlugos from Planet10 added bracing to cure the resonance we got on the first try. A couple panels went into each horn, and some external slats on the outsides of each horn, perpendicular to the internal braces. A spine of bracing was also applied to the rear panels.
Altogether the speaker is greatly improved. There is still some boxyness and woodyness, and tapping the wood still has a little resonance, but it is listenable now, at least for me. I have a high tolerance for audio pain when the rest of the presentation is this good.
I plan to add stuffing to the inner chamber tonight which should further improve things by damping down the middle and upper frequencies and prevent them from being amplified by the horn. I will also paint them with a couple thick latex coats to damp the wood a little more. But of course I had to listen first, so I could learn what stuffing does - besides I just couldn't wait any longer. It feels good to check this project off the 'to do' list. It has been a long time coming.
But I do intend to build it all over again a couple more times using different materials which should require significantly less resonance control, and so they should build much faster. I have high hopes for those. The baltic birch is just not my cup of tea dispite its long history as material of choice for single driver designs.
These things have incredible tone, dynamics, clarity, detail beyond your wildest imagination. Imaging is surreal. I can't listen with my eyes closed, the imaging is too distracting. I keep feeling there is someone really there and my subconscious reflex opens my eyes to see. With further improvement in the resonance and type of wood I think it will be something very special. The drivers are the star of course, they really deserve the finest cabinet possible, and reward richly for the effort.
So yes, if you come over on May 17th you will be able to hear them this time. Maybe even further revisions... 8)
(http://www.audionervosa.com/gallery/128_29_04_08_2_36_01_0.JPG) (http://www.audionervosa.com/gallery/128_29_04_08_2_36_01_1.JPG)
(http://www.audionervosa.com/gallery/128_29_04_08_2_36_01_2.JPG)
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Wow, that's killer Rich. You should sell those cabs, I'm sure somebody would pay for them. Have you tried any BlackHole 5 or dynamat or modeling clay or similar materials to tame the resonance? They'd all be most at home inside the box of course. The modeling clay especially could be fun because it's non-permanent, stays soft forever, and can be moved and tweaked in no time flat.
Nice work Rich, I'd really like to hear those. The widebander thing is right up my alley.
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Thanks Mike! I listened again tonight (2nd impresion) and it is not as bad as I may have let on first post. It's easy to listen through the remaining wood, but it would be nice to clear it out altogether. Or if wood must remain, make it pine or something that sounds good naturally.
I have not tried any of that stuff, but about every 4 months Carl is recommending I try black hole for something or other. John uses plasticlay in TTs, but I never thought about it in a speaker box. Good idea! This speaker's designer, Dave Dlugos believes that damping birch only makes the resonance lower in frequency which sounds worse. He tends to lean toward tensioning and bracing it to raise the resonant frequencies out of the passband. I like the idea, but in practice it is more difficult to build, but the results seem to be worth it. I am really enjoying this speaker.
I hope what is happening is the midrange freqs inside the speaker are being woodied up inside the box and more in the horn while amplified in the horn. Some wool inside will damp mids coming out of the tuned port, and might solve it.
I'd like you to hear them too!!!! I am considering making them, but I don't know where in the hell I would find the time. Lots more development to do before they could wear my brand name, but potential is there.
My wife dug the look. She said they looked cool, but strange. I think they are right out of the Millenium Falcon's dedicated 2ch cabin. Painted silver with red leather padding on the sides between the slats... And big 2 inch thick power couplings going in both sides, and few blinking lights and screens on the front. haha...
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Rich, Very cool. Another suggestion -- laminate, with green glue or not, something completely different with altogether different resonant characteristics from wood. Phenolic -- the high grade linen composition type might be a good choice. Well, this is about experimentation, isn't it? :D At least it's a lot easier than the edge glued plywood :-).
Looks like my "Uber Fonken" F120A Fonkens are not too far off., so it will be interesting to see how these compare to the Feastrex drivers when Mike finishes his cabinets (miklorsmith, different Mike.)
The progress sounds good and promising.
-- Jim
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I like the constrained layer idea. It is from the damping school. I have to do that on another speaker than this, too much effort to make it tensioned. If I damp it is the opposite direction. Either way damped or tensed, the resonance is forced out of band where the wood will vibrate. Damped requires mass, which makes a speaker heavy. Legacy's will be the last heavy speakers I ever own. :shock:
Your F120As are getting the super dot treatment right? What's it called again? You guys can have your own horn fest out there pretty soon!! Mike is getting itchy to build the Maikos too. He is just waiting for me and Phil Townsend to make all the dumb mistakes first.
I think I will try the edge glued scenario next, but with a twist.. I would like to find a source of phenolic like WIlson uses.
Thanks
Rich
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Rich,
The F120As have already been EnABLed by Bud -- who had nothing but good things to say about them; very good things. I then sent the drivers to Planet 10 so they could use them to develop and tweak the Fonken for the F120A. Beyond that, the drivers will be left stock for now. Dave tells me that the design is done and wood will be cut shortly.
Didn't know wilson used phenolic, but makes sense -- the stuff, especially the super fine grades are super dense and heavy, and it's not cheap either.
I'm confident you will come up with something great though, whatever it ends up being. Then I may have an amp to send you.
-- Jim
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I think I will try the edge glued scenario next, but with a twist.. I would like to find a source of phenolic like WIlson uses.
Rich,
Very cool, I'd love to hear these.
US Plastics has several varieties of Phenolic sheet in various thicknesses of 24 x 48 inches and 48x48.
http://www.usplastic.com/catalog/category.asp?catalog%5Fname=usplastic&category%5Fname=79&Page=1
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Thanks Mike, I get their catalog twice a year but never thought to look there!!
I stuffed them with LOTS of poly wool yesterday, about 10oz each. Too much. It helped the midrange woodyness a lot, but killed the magic and detail. I took out most of it leaving only 3oz per speaker, much better, but still some stuffyness for the wool and still a trace of woodyness, so a compromise is gonna be needed. Big surprise! haha
I spoke to a friend in MA who just recieved his new Feastrex 9" drivers, about to start building his cabinets. I can't wait to hear those.
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Maybe you guys can help me understand this. Why does a horn have a horny coloration?? It is the geometry of the horn, or is it the resonance of the material the horn is made from. The horn should just be an amplifier, right? If the material it was made from was totally nonresonant, would the horn give a coloration? Trying to decide if rebuild with new material or redesign with rounded shapes.
Maybe squared off DIY type horns are more prone to the empty box sound than structurally stronger and rounded spherical horn?
Has anyone ever heard avante garde, with ABS spherical horns? Are they noticably colored? I assume that they will sound different as you move in and out of the center.
Thanks
Rich
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Rich,
FWIW, I can't ever recall ever hearing a horn of any kind that didn't have a bit of "horn" sound to it. I can't say with absolute authority but I suspect that it has to do with the fact that there is a very narrow band of frequencies which are cou0pled more efficiently to the room due to it being a horn -- if that makes any sense. In other words, every horn has a resonant frequency, and it is always in the audible range, where as resonant frequencies of boxes can be pushed up or down to reduce their effect.
I think what it comes down to is whether you like it or not, and certainly there are horns and then there are horns. Those monster Cogent field coil horns are incredible and I culd easily live with their horn "colorations". I've never heard what one would call a completely neutral horn.
When talking with Joe Cohen last year, he speculated that the real ticket for these drivers would be a TL of some sort, but all that remains to be seen.
-- Jim
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Thanks Jim, that makes sense, especially in a boxish horn where reflections in the horn will emphasize midrange wavelengths. I do like the aliveness and sensitivity of horns, I may be stricken.
I hooked up the Quads again today to get contrast and a sanity check. I'm glad I did, I must have been going insane to think the horny coloration "wasn't that bad..." Lots of ringing wood panels all adds up. Back to the drawing board.
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OK, time for next installment in this saga... (compulsion?)
(http://www.audionervosa.com/gallery/128_29_05_08_5_53_14.JPG)
Another copy of the previous wooden design, called Maiko, this time made of plastic, so no wood signature at all. It is a very dead material, so the midrange is quiet. Ahhhhhhhh........ There is no bracing whatsoever in this structure. The material is mostly self damping above 100Hz, maybe even lower. There is still a bit of extra bass but it is quiet and easy to ignore. I think I can stretch that out of existance. The material is a royal PITA to work with.
Sound is improved dramatically over the previous wooden carcass. The baltic birch coldness is gone. Some of the wood excitement is gone too, but the quietness is always better than excitement. Let the music be exciting. The sound of the driver comes through unaffected by box noise, and is very enjoyable.
I will still be building this design at least one more time, with a composite structure next. I would like to build it in aluminum too. Time to learn how to weld!
Rich
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is that TREX deck material?
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Yes. I would not use it again. This morning I am not impressed with it. But it did solve the midrange resonance.